CHAPTER XII 
PLUM DISEASES 
Tue plum furnishes food and habitation for several parasitic 
fungi and bacteria. It is also affected with other ills caused 
by frost and other factors not generally understood. Many 
of these diseases are native in their origin, so that often 
‘European plums are highly susceptible to important diseases 
in America. 
Brown-Rotr 
Caused by Sclerotinia cinerea (Bon.) Schrot. 
No disease gives the commercial plum-grower so much trouble 
as brown-rot. It occurs more or less every year, affects the 
ripe or ripening fruit, and destroys it absolutely (Fig. 99). It 
is equally annoying and destructive in small home gardens, 
rotting the fruit just at the time when it is ready for use. 
It is said that thin-skinned varieties are more resistant to 
brown-rot than others. It is also said that the Triflora, Amer- 
icana and Japanese groups are more injured than plums in other 
groups. The Burbank, Abundance and Satsuma are said to be 
most susceptible, while several varieties are listed as resistant. 
Among the latter may be noted: Hansom, Clinton, Forest 
Rose, Indiana, Miner, Nebraska, Prairie Flower and others. 
It is-to be noted that most of the list of so-called resistant 
plums are varieties of minor importance; at least they are not 
leading American plums. And it is doubtful whether the Bur- 
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